21025782 has 24 divisors (see below), whose sum is σ = 45706440. Its totient is φ = 6985440.

The previous prime is 21025759. The next prime is 21025793. The reversal of 21025782 is 28752012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4194 + ... + 7722.

It is an arithmetic number, because the mean of its divisors is an integer number (1904435).

Almost surely, 2^21025782 is an apocalyptic number.

21025782 is an abundant number, since it is smaller than the sum of its proper divisors (24680658).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21025782 is a wasteful number, since it uses less digits than its factorization.

21025782 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3868 (or 3865 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 21025782 is about 4585.3878789040. The cubic root of 21025782 is about 276.0052771518.

Adding to 21025782 its reverse (28752012), we get a palindrome (49777794).

The spelling of 21025782 in words is "twenty-one million, twenty-five thousand, seven hundred eighty-two".